Term
| What is the basis for classifying muscle fibers? |
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Definition
| Their enzymes & enzymatic activities (aerobic vs anaerobic metabolism) |
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Term
| Do most muscles have more white fibers or red? |
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Definition
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Term
| Do adductor muscles primarily use oxidative or glycolytic metabolism? What colour are they? |
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Definition
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Term
| Do longissimus muscles primarily use oxidative or glycolytic metabolism? What colour are they? |
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Definition
| glycolytic ; pale, more pink |
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Term
| What is the main muscle in pork chop? |
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Definition
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Term
Order the following types of meat in increasing degree of pigmentation
Pork, Beef, Lamb, Poultry |
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Definition
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Term
True or False
Differences in pigmentation between muscles can be observed with beef and lamb |
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Definition
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Term
True or False
Differences in pigmentation between muscles can be observed in poultry and pork |
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Definition
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Term
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Definition
| an iron-containing compound that stores O2 in muscle fibers |
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Term
Describe the following characteristics of oxidative fibers
Colour
Mitochondria
Cytochromes
Enzyme activity
Twitch/contraction speed
Size |
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Definition
-redder in colour
-more, larger mitochondria
-more cytochromes
-succinate dehydrogenase & cytochromse oxidase activities are strong
-ATPase and phosphorylase activitise are weak
-slow twitch
-smaller diameter than white fibers |
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Term
| How does myoglobin differ from hemoglobin? |
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Definition
| Myoglobin stores oxygen in muscle, hemoglobin transports oxygen in blood |
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Term
| Are red fibers oxidative or glycolytic? |
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Definition
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Term
| What is the value of fat droplets found in oxidative fibers? |
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Definition
| source of energy used aerobic metabolism |
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Term
| Are muscles involved with respiration, chewing, maintaining posture etc. slow or fast twitch? Why? |
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Definition
| slow twitch, don't want these muscles to be easily fatigued |
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Term
| Why do oxidative fibers tend to have more capillaries than glycolytic fibers? |
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Definition
| to facilitate oxygen and nutrient transfer |
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Term
| Why do oxidative fibers tend to be smaller in diameter than glycolytic fibers? |
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Definition
| to reduce diffusion distance & speed up the transfer process |
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Term
| Why do glycolytic fibers appear to be more white? |
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Definition
| because they have very small amounts of myoglobin |
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Term
Describe the following characteristics of glytolytic fibers
Colour
Mitochondria
Cytochromes
Enzyme activity
Twitch/contraction speed
Size |
|
Definition
-white in colour
-smaller & fewer mitochondria
-fewer cytochromes
-weak aerobic enzyme activity
-strong ATPase and phosphorylase activity
-fast twitch
-larger in diameter |
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Term
| What is the energy reserve used by fast twitch muscles? |
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Definition
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Term
| What muscles are more easily fatigued, fast twitch or slow twitch? |
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Definition
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Term
| Why do white fibers have a more developed sarcoplasmic reticulum & T-tubules? |
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Definition
| -used for transmitting AP across muscle fiber & stimulating contraction, important for achieving fast contraction |
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Term
| Do intermediate fibers more closely resemble the metabolic pathway of red or white fibers? Why? |
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Definition
| white, because the enzyme activities predominantly involve ATPase and phosphorylase |
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Term
| What colour are intermediate fibers? |
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Definition
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Term
| What bundles of muscle fibers called? |
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Definition
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Term
| What is another term for muscle fibers? |
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Definition
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Term
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Definition
| contractile organelle inside the muscle fiber |
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Term
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Definition
| protein filiments found inside myofibrils |
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Term
| What is the basic contractile structure of a a muscle fiber cell? |
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Definition
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Term
| What volume of the muscle fiber is attributed to myofibrils? |
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Definition
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Term
| What are the two striations of myofibrils? Which is dark in regular light, and which is light? |
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Definition
anisotropic (dark)
isotropic (light) |
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Term
| What causes the transverse striations of myofibrils? |
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Definition
| arrangement & overlapping of thick & thin myofilaments |
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Term
| Where is a Z disk (Z line) relative to the I band? |
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Definition
| in the center of the I band |
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Term
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Definition
| repeating structural unit of myofibril, basic unit for contraction/relaxation cycle of the muscle |
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Term
| How many A & I bands are found in one sarcomere? |
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Definition
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Term
| When is sarcomere length the greatest? |
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Definition
| during muscle relaxation (even greater when stretched) |
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Term
| What is cold shortening and when does it occur? |
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Definition
| shortening of the sarcomeres due to rapid chilling of meat |
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Term
| When sarcomere length decreases, what happens to the distance between Z lines? |
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Definition
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Term
| How can you manipulate the carcass postmortem to increase sarcomere length? |
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Definition
| use the weight of the carcass to stretch muscles, make selective cuts to stretch certain muscles |
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Term
| How many thin filaments surround 1 thick filament? |
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Definition
|
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Term
| How many thick filaments surround 1 thin filament? |
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Definition
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Term
| What type of filament is found in A bands? |
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Definition
|
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Term
| What is the predominant protein in thick filaments? |
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Definition
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Term
| What is the effect on myosin when treated with trypsin? |
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Definition
Can produce...
light meromyosin: backbone of thick filament
heavy meromyosin: can be split into 2 subfragments |
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Term
| What is HMM-1 composed of? |
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Definition
| the two active heads of myosin |
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Term
| What is the function of HMM-1? |
|
Definition
-bind actin in thin filaments
-hydrolyse ATP to ADP |
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Term
| Describe the arrangement of myosin in a thick filament |
|
Definition
-1/2 of molecules face 1 Z line, 1/2 face the opposite Z line
-short headless zone in the middle of the filament |
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Term
| What filaments make up the I band |
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Definition
|
|
Term
True or False
Thin filaments overlap a portion of the A band |
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Definition
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Term
| What is the predominant protein found in thin filaments? |
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Definition
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Term
| What is the function of tropomyosin & troponin |
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Definition
| tropomyosin changes depth in response to troponin, allowing myosin heads to row against actin molecules |
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Term
| What happens when Ca2+ is available? |
|
Definition
-it attaches to troponin
-conformation of the protein changes
-cross bridge binding sites on actin is exposed
-myosin heads can attach |
|
|
Term
| what are the 3 subunits of troponin? |
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Definition
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Term
| Where is a flexor muscle located on a limb, relative to the joint to which it bends? What do flexor muscles do? |
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Definition
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Term
| Where is an extensor muscle located on a limb, relative to the joint to which it bends? What do extensor muscles do? |
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Definition
on the opposite side
extends/straightens out |
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Term
| What side of the limb is the biceps brachii located on? Does it flex or extend the elbow? |
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Definition
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Term
| What side of the limb is the triceps brachii located on? Does it flex or extend the elbow? |
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Definition
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Term
| What are some functions of muscles? |
|
Definition
-produce a desired movement
-stabilize joints
-provide smooth control over a movement |
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Term
| What do adductor muscles do? |
|
Definition
| pull the limb towards the median plane |
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Term
| What do abductor muscles do? |
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Definition
| pull the limb away from the median plane |
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Term
| Are sphincters striated or smooth? |
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Definition
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Term
| These muscles surround an opening.... |
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Definition
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Term
| Do humans have cutaneous muscles? |
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Definition
|
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Term
| Where are cutaneous muscles found? |
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Definition
| between the skin & deep fascia |
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Term
| What is an agonist? Antagonist? |
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Definition
Agonist: a muscle that directly produces a desired movement
Antagonist: muscle that opposes the action of the antagonist |
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Term
| A muscle that assists the agonist is known as... |
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Definition
|
|
Term
| A muscle that stabilizes a joint is known as... |
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Definition
|
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Term
| Is a prime mover an antagonist or agonist? |
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Definition
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|
Term
| What is the most stable point of muscle attachment? |
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Definition
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Term
| Where does most of the movement occur when a muscle contracts? |
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Definition
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Term
| What are the components of skeletal muscle? (5) |
|
Definition
-muscle proper
-fasiculi
-myofibers
-myofibrils
-myofilaments |
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Term
| What is the function of the epimysium? |
|
Definition
| covers & protects the muscle |
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Term
| What effect does connective tissue have on eating quality? |
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Definition
| more connective tissue = less tender |
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Term
| Do locomotion muscles have more or less connective tissue? |
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Definition
|
|
Term
| What binds muscle fibers into fasiculi? |
|
Definition
|
|
Term
True or False
The perimysium is a form of connective tissue |
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Definition
|
|
Term
| What covers & protects a myofiber? |
|
Definition
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|
Term
|
Definition
| a membrane which surrounds a muscle fiber |
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Term
| Why is the elastic property of sarcolemma important? |
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Definition
| -to be able to change shape during contraction & extension |
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Term
|
Definition
| a series of tubules which carry AP across the muscle cell |
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Term
| What is a sarcoplasm? What are the 3 major organelles found within it? |
|
Definition
the 'cytoplasm' of a muscle fiber
-nuclei, mitochondria & sarcoplasmic reticulum |
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|
Term
| Are muscle fibers mononucleated or multinucleated? |
|
Definition
|
|
Term
| What is the difference between tendon & fascia? |
|
Definition
tendon connect muscle to bone
fascia connect muscle to other muscle |
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